Distributed computation is about time and state. That is, in order for more than one component to communicate, state must be shared, and all that takes time.
Most programmers anthropomorphize their work. They think about one thread of control carrying out the entire program in the same way they would if they had to do the job themselves. Modern computers, however, switch between tasks very quickly, and in multi-core, multi-CPU, or distributed systems, two events may take place at exactly the same time. Defects rush to fill the gap between the programmer's model of how a program executes and what happens in reality. These defects are related to unexpected interactions between threads, processes, time, and information. These interactions happen through shared state: semaphores, variables, the file system, and, basically, anything that can store information.
ASP.NET Bad Practices: Non-Serializable Object Stored in Session
HttpSessionState attribute can damage application reliability.HttpSessionState object, its attributes and any objects they reference in memory. This model limits active session state to what can be accommodated by the system memory of a single machine. In order to expand capacity beyond these limitations, servers are frequently configured to persistent session state information, which both expands capacity and permits the replication across multiple machines to improve overall performance. In order to persist its session state, the server must serialize the HttpSessionState object, which requires that all objects stored in it be serializable.In order for the session to be serialized correctly, all objects the application stores as session attributes must declare the
[Serializable] attribute. Additionally, if the object requires custom serialization methods, it must also implement the ISerializable interface.Example 1: The following class adds itself to the session, but since it is not serializable, the session cannot be serialized correctly.
public class DataGlob {
String GlobName;
String GlobValue;
public void AddToSession(HttpSessionState session) {
session["glob"] = this;
}
}